JPH02265525A - Eye width detecting device - Google Patents

Abstract

PURPOSE:To obviate a mechanical connection for detection, and eliminate the occurrence of a wear, a friction sound and unnecessary contact feeling by providing a slide means for sliding a machine body in the direction of right and left eyes with a base, and an optical detection means for detecting relative displacement between the base and the machine body. CONSTITUTION:A slide guide part 12 and a movable base 13 are provided on the base 11 of an eye refractometer 11 having a built in eye width detecting device, thereby constituting a slide bed 14. A machine body 15 is installed on the slide bed 14. The front part of the bed 14 is provided with an objective lens barrel 16 and the rear part with a TV monitor. An arithmetic means 18 is built into the machine body 15. An inspector operates a control rod 19 and a vertical operation ring 20 for adjusting the alignment of the machine body 15 so that the optical axis of the objective lens barrel 16 of the machine body 15 is properly aligned with the eye E of a subject fixed at a constant position with a face fixing base 22, and a suitable operation distance is obtained. When a measurement switch 21 is pressed after alignment adjustment, the refraction value of the inspected eye is automatically calculated with the arithmetic means 18, and the result of the calculation is displayed on the TV monitor and printed with a printer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a pupil distance detection device that is incorporated into various ophthalmological machines such as an autorefractometer.

[Prior Art] Conventionally, devices using potentiometers have been widely put into practical use as interpupillary distance detection devices incorporated in autorefractometers and the like.

FIG. 8 shows the main part of a conventional example using this potentiometer, and shows a cross section along a sliding shaft 3 that slides the main body 2 on the base 1 in the interpupillary direction of the eye to be examined. At both ends of the slide M3, a meshing wheel 4a that rotates in a direction toward and away from the eye to be examined is provided.
, 4b are attached, and a block 6 is slidably fitted to a guide shaft 5 provided in the machine body 2.
The pin 6a protruding downward is the guide groove 1 provided in the base l.
It is movable in the # rearward direction along a. A wire 8 is passed between the pulley 7a attached to this block 6 and the pulleys 7b and 7c attached to the machine body 2 side, and the wire 8 rotates the pulley 7c of the potentiometer 9, and the pulley 7c of the potentiometer 9 is rotated. Movement in the left and right direction is detected as a change in the output of a resistor connected to the potentiometer 9.

[Problems to be Solved by the Invention] However, the conventional example having such a configuration has the following drawbacks.

(1) Since only the amount of movement in the horizontal direction corresponding to the interpupillary distance is detected from the sliding movement of the machine body 2 in the longitudinal and horizontal directions, many separate members such as the block 6 and the guide shaft 5 are required. This makes the process more complicated and costs higher.

(2) Since the wire 8 is likely to slip on the pulleys 7a, 7b, and 7C, there is a risk that the reference value of the potentiometer 9 will deviate.

(3) Since a mechanical connection is used for detection, there are concerns about wear, friction noise, unnecessary contact sensation, etc.

SUMMARY OF THE INVENTION An object of the present invention is to provide an interpupillary distance detection device that eliminates the drawbacks of the conventional examples described above and uses an optical detection method without using almost any mechanical mechanism.

[Means for Solving the Problems] In order to achieve the above object, the interpupillary distance detection device according to the present invention includes a sliding means for sliding the main body of the machine in the direction of the left and right eyes with respect to the base; The apparatus is characterized by comprising an optical detection means for detecting a change in relative position between the base and the machine body due to sliding by the sliding means based on a projected position of a light source image on an optical position detection element. It is.

[Operation] The interpupillary distance detection device having the above-mentioned configuration can detect the interpupillary distance between the left and right eyes of the subject without using almost any mechanical mechanism, so it is structurally simple and requires no mechanical mechanism. The problems caused by this will be resolved.

[Example] The present invention will be described in detail based on the example illustrated in FIGS. 1 to 7.

Figure S1 shows a schematic diagram of, for example, an ocular refractometer incorporating the interpupillary distance detection device according to the present invention, in which a sliding guide part 12 that can be slid back and forth and left and right within a certain range is provided on a base 11, A movable base 1 that can slide left and right within a certain range on this sliding guide part 12
3 are constructed, and these constitute a sliding table 14. A machine main body 15 is mounted on the sliding table 14, and an objective lens barrel 16 is provided at the front of the machine main body 15, a television monitor 17 is provided at the rear, and an arithmetic processing means 18 is built inside. Further, an operating rod 19 is attached to the movable base 13, and upper and lower rings 20 are rotatably provided at the base of the operating rod 19, and measurement switches 21 are provided at the upper ends, respectively. In operation, the machine body 15 on the slide table 14 can be slid in a desired direction by tilting the rod 19 in any direction, and the height of the machine body 15 can be freely adjusted by rotating the upper and lower rings 20. is now possible. Also.

On the subject P side of the base 11, there is provided a face fixing base 22 to which a chin rest 22a and a forehead rest 22b are attached to support the face of the subject P.

The examiner observes the television monitor 17 so that the optical axis of the objective lens barrel 16 of the machine body 15 is correctly aligned with the eye E, which is fixed in place by the face fixing table 22, and is at an appropriate working distance. When the measurement switch 21 is pressed after this alignment adjustment, the refractive value of the eye to be examined is automatically calculated by the arithmetic processing means 18, and the result is displayed. It is displayed on the television monitor 17 or printed by a printer.

FIG. 2 shows an embodiment of the interpupillary distance detection means built into the sliding table 14, in which the left-right direction is the left-right sliding direction of the sliding table 14, and the up-down direction is the front-back sliding direction. A small light source body 31 consisting of is attached to the sliding guide part 12,
Further, a pinhole plate 32 provided with a pinhole 32a,
CCDCCharge Coupled Device
) element or PSD (Position 5ensi
Optical position detecting elements 33 each consisting of an optical position detecting device (active device) element or the like are respectively attached to the movable table 13, and the small light source body 31 and the pinhole 32a are spaced apart from each other in the front-rear direction and by W in the left-right direction. The light from the small light source 31 passes through the pinhole 32a and is projected onto the optical position detection element 33 located to the right of the pinhole plate 32 by a distance. When the sliding table 14 slides left and right, the small light source 31 and pinhole 32
a changes, and this change is detected as a change in the projected image position MA on the optical position detection element 33, as shown in the enlarged view of the main part in FIG. As shown in the principle diagram of FIG. 4, the following relationship exists between the projected image position l of the small light source 31 on the optical position detection element 33 and the horizontal sliding amount W of the machine body 15 with respect to the base 11. There is a proportional relationship.

J2:L=D:W From this proportional relationship, the left-right sliding amount W can be determined as follows.

W=D −L/1 In the above configuration, the sliding table 14 is slid so as to face each of the left and right images of the eye E to be examined, and the projected image position of the small light source 31 on the optical position detection element 33 during hibernation is adjusted. i1N is detected, the actual left-right sliding amount W corresponding to hibernation is determined by the arithmetic processing means 18, and the absolute value of the difference is taken as the interpupillary distance.

In the embodiment shown in FIG. 5, the small light source body 31 is provided on the movable table 13 side like the pinhole plate 32 and the optical position detection element 33, and the light from the small light source body 31 is directly transmitted to the optical position detection element 33.
A light shielding plate 41 is provided to prevent the light from being detected, and a reflector 42 having a reflective surface 42a is attached to the sliding guide portion 12. As shown in the principle diagram of FIG. 6, the small light source 31 is spaced from the pinhole 32a by an interval L° in the front-rear direction, and from the reflective surface 42a by a distance W in the left-right direction, similar to the previous embodiment. have a proportional relationship.

i:L'/2=D:W From this proportional relationship, the left-right sliding amount W can be determined as follows.

W=D −L' /2 In addition, the electrical connections between the small light source 31 and the optical position detection element 33 can be integrated on the movable table 13 side, improving work efficiency.
It is effective in improving durability, etc. Note that the reflective surface 42a may be a convex curved surface or a cylindrical surface having an axis in the front-rear direction other than a flat surface, and in these cases, the resolution of the optical position detection element 33 is not required as compared to when the reflective surface 42a is a flat surface.

The embodiment shown in FIG. 7 is an improvement of the embodiment shown in FIG. An imaging lens 44 is provided in place of 32. By providing the reflective surface 42a and the optical position detecting element 33 at the focal position of each lens 43° 44, it is possible to prevent the image formation of the small light source 31 onto the optical position detecting element 33 from blurring, and more precise measurement can be performed. . In this embodiment, the sliding guide part 12 and the movable base 1
3 may be replaced, or the reflective surface 42 may be replaced.
When a is a plane in the front-rear direction, the reflector 42 may be attached to the base 11.

[Effects of the Invention] As explained above, the interpupillary distance detection device according to the present invention converts changes in the sliding position in the left and right direction of the sliding table on which the machine body is mounted into changes in the projection position of the light beam onto the optical position detection element. 1) Mechanical connections are not required, and parts and assembly costs can be reduced. Furthermore, there is no wear due to friction, no friction noise, no unnecessary contact feeling, etc., and there are advantages in the durability of the detection element.

[Brief explanation of drawings]

1 to 7 show an embodiment of the pupil distance detection device according to the present invention, FIG. 1 is a schematic diagram of an eye refractometer incorporating the pupil distance detection device, FIG. 2 is a configuration diagram, and FIG. 3 is an enlarged view of the main parts, FIG. 4 is a principle diagram, FIG. 5 is a configuration diagram of another embodiment, FIG. 6 is a principle diagram, and FIG. 7 is a configuration diagram of yet another embodiment. 8
The figure is a configuration diagram of a conventional example. 11 is a base, 12 is a sliding guide, 13 is a movable base, 1
4 is a sliding table, 15 is the main body of the machine, 16 is an objective lens barrel, 17 is a television monitor, 31 is a small light source, 32 is a pinhole plate,
32a is a pinhole, 33 is an optical position detection element, 41 is a light shielding plate, 42 is a reflector, 42a is a reflective surface, 43 is a projection lens, and 44 is an imaging lens. Patent applicant Canon Co., Ltd.

Claims (1)

[Claims] 1. A sliding means for sliding the machine body relative to the base in the left-right eye direction, and a light source on the optical position detection element that detects changes in the relative position between the base and the machine body due to sliding by the sliding means. What is claimed is: 1. An interpupillary distance detection device comprising: an optical detection means for detecting based on the projected position of an image.